Mutagen vs Carcinogen Mutagen and carcinogen are two terms that have a lot in common. There is a potential that a single substance could be both of them at the same time and be only one of the two, as well.
A curb bit is a type of bit used for riding horses that uses lever action. It includes the pelham bit and the Weymouth curb along with the traditional curb bit used mainly by Western riders. Kimblewicks or Kimberwickes are modified curb bits, and a curb bit is used in a double bridle along with a bradoon.
The Tom Thumb and any other bit with shanks are curb bits, which use a leverage action. So, if the bit has shanks, it is always a curb bit, and never a snaffle. The shanks on a curb bit do not have to be long to put some pressure over the top of the horseâs head, and behind the chin. That is how a curb bit works. So even a bit with two or three-inch shanks is a curb bit.